Biosynthesized nickel oxide honeycomb nanostructures for DSSC counter electrode: a joint experimental and density functional theory study

Abstract The urgent need to address fossil fuel challenges has led to a surge in green energy technologies, including solar cells. Nanodimensional particles, particularly 2D nanostructures, have shown great potential in these technologies due to their high surface area-to-volume ratio. Nickel oxide (NiO) is a promising p-type semiconductor for solar cell photo-cathodes, offering remarkable physical and chemical properties at a relatively low cost. However, its surface morphology, area, and pores have a significant impact on performance. Traditional chemical synthesis methods for NiO nanostructures have several drawbacks, including the use of hazardous precursors. To address this, we present for the first time a novel bioengineering method using bamboo shoot extract to produce 2D NiO nanostructures. The results have been supported by Density Functional Theory (DFT) calculations. The DFT calculations revealed that NiO is a p-type semiconductor with direct band gap for spin-down at Г. The results show that the bioengineered NiO nanostructures exhibit high crystallinity and a honeycomb-like morphology. We successfully integrated these nanoparticles into a dye-sensitized solar cell (DSSC), demonstrating their viability as a counter electrode. The cell exhibits promising performance, with a short-circuit current density of 0.113 mA cm −2 and an efficiency of 0.0057%. This study presents a straightforward, cost-effective, and environmentally friendly method for bioengineering NiO honeycomb-like nanostructures, thereby paving the way for sustainable energy solutions.